Abstract We consider a one-dimensional system of four inelastic hard spheres, colliding with a fixed restitution coefficient r, and we study the inelastic collapse phenomenon for such a particle system. We study a periodic, asymmetric collision pattern, proving that it can be realized, despite its instability. We prove that we can associate to the four-particle dynamical system another dynamical system of smaller dimension, acting on { 1 , 2 , 3 } × S 2 , and that encodes the collision orders of each trajectory. We provide different representations of this new dynamical system, and study numerically its ω-limit sets. In particular, the numerical simulations suggest that the orbits of such a system might be quasi-periodic.